Defining oligometastatic hormone sensitive prostate cancer and clinically significant outcomes: Implications on clinical trials?

Abstract

PurposeWith the current movement toward treating oligometastatic hormone sensitive prostate cancer (OMPC), we design a study with the objective of gathering opinions regarding what would be considered a clinically significant benefit from such treatments. MethodsData was collected from physicians of the Society of Urologic Oncology using a self-administered questionnaire using SurveyMonkey. The questionnaire was designed to obtain characteristics on clinical practice of the respondents, definitions used for OMPC and also what would be considered a clinically significant benefit according to the respondents. We present a descriptive analysis of the responses obtained. ResultsWe obtained 119 responses (response rate of 12.6%) after sending the questionnaire twice with one month apart. Most of them being staff/faculty (89%) practicing in the United States of America (84.87%). Most of the responders referred that a significant proportion of their practice comes from PC patients. Most defined OMPC <3 bone/lymph node metastasis seen with conventional imaging, only 26.9% of the responders used positron emission tomography. Regarding the clinical benefit of metastasis-oriented treatment, a curing rate >10% or an increase in 1 year of androgen deprivation therapy-free survival would make the treatment worthwhile. We present examples of sample size calculations for future clinical trials using these parameters as an expected “clinically-significant” benefit. ConclusionThis study shows that most clinicians still support the use of conventional imaging to define OMPC. Our findings show that a curing rate of a minimum of 11% and an androgen deprivation therapy-free survival at 1 year are considered clinically significant and this should be used for estimating the sample size in future clinical trials.